31 lines
909 B
Plaintext
31 lines
909 B
Plaintext
func euler_method(t0, t1, k, step_size) {
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var results = [[0, t0]]
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for s in (step_size..100 -> by(step_size)) {
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t0 -= ((t0 - t1) * k * step_size)
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results << [s, t0]
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}
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return results;
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}
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func analytical(t0, t1, k, time) {
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(t0 - t1) * exp(-time * k) + t1
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}
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var (T0, T1, k) = (100, 20, .07)
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var r2 = euler_method(T0, T1, k, 2).grep { _[0] %% 10 }
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var r5 = euler_method(T0, T1, k, 5).grep { _[0] %% 10 }
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var r10 = euler_method(T0, T1, k, 10).grep { _[0] %% 10 }
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say "Time\t 2 err(%) 5 err(%) 10 err(%) Analytic"
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say "-"*76
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r2.range.each { |i|
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var an = analytical(T0, T1, k, r2[i][0])
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printf("%4d\t#{'%9.3f' * 7}\n",
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r2[i][0],
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r2[i][1], ( r2[i][1] / an) * 100 - 100,
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r5[i][1], ( r5[i][1] / an) * 100 - 100,
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r10[i][1], (r10[i][1] / an) * 100 - 100,
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an)
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}
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